Nanosatellites are satellites with masses of less than about 10 kg. Although sometimes referred to as picosatellites, in this disclosure, satellites with masses between 0.1 to about 1 kg are also included in the nanosatellites family. Nanosatellites are gaining popularity for use in applications including remote sensing, communication, and space research, in part because of the relatively low cost of nanosatellites as compared to the larger satellites.
A single satellite in low Earth orbit (LEO) has a time-limited line of sight with a ground location. Consequently there may be large gaps in coverage until the ground track repeats. However, a network of satellites can maintain a near constant radio and visual coverage or simultaneously provide coverage of multiple regions.
One advantage of using low-cost nanosatellites is the ability to launch numerous platforms for a similar cost as launching a larger satellite. Thus, a network of low-cost nanosatellites can be launched and used to maintain high temporal resolution sensing. In this manner, nanosatellites can form the space segment of a communications network or an Earth observation sensor network.
At a minimum, in order to maintain the network integrity, the satellites need to keep a line of sight with each other. Due to gravitational and drag perturbations in LEO, such a formation-flying configuration cannot be maintained for more than few weeks without orbital correction maneuvers. The need for orbital correction maneuvers may arise in spite of the fact that the satellites are often deployed from a common launcher.